Currently, determining air quality is not a simple endeavor. Particle counters such as light scattering particle counters and light blocking direct imaging particle counters may be used, but these devices have the drawback of not being sufficiently sensitive to detect extremely small particles at a competitive price point, and furthermore, such devices may include complex systems with moving parts that are prone to wear and tear over time. These drawbacks are barriers to the adoption of such sensors in an indoor environment such as a home or office environment where the effect of small particles on indoor air pollution is becoming a health concern.
The problem of air pollution is also a concern in outdoor settings, as it affects the performance of machines in the built environment such as solar panel arrays, heating ventilation and air conditioning (HVAC) systems, etc., and also because it affects how people live, work, and play outdoors. As one specific example, solar panels lose their effectiveness as particulate matter accumulates on their surfaces. However, since various other factors contribute to the effectiveness of a solar panel array, such as age of the solar panels, ambient operating temperature, shade and overcast skies, etc., it may be difficult to determine the extent to which a measured drop in effectiveness is affected by particulate build up on the front face of the solar panels. As a result, it is a challenge for the operator of the solar panel array to accurately determine when the solar panels should be cleaned to remove particulate build up. As a result, costly unneeded cleanings may occur, or the solar panels may not operate at optimum efficiency. The light scattering particle counters and light blocking direct imaging particle counters discussed above are not suitable for use in such large solar panel arrays due to their high cost relative to their sensitivity. Further, such sensors with moving parts may not be suitable for use in such an outdoor setting, where they may deteriorate more rapidly.